Journal of Sciences, Islamic Republic of Iran 24(3): 243- 257 (2013) http://jsciences.ut.ac.ir University of Tehran, ISSN 1016-1104 Morphological and systematic interpretation of some Late Cretaceous (Turonian-Santonian) irregular echinoids, Kopet-Dagh Basin, NE Iran J. Noorbakhsh Razmi1, A. A. Aryaei1, M. Taherpour Khalil Abad2* and A. R. Ashouri1&3 1 Department of Geology, Mashhad Branch, Islamic Azad University, Mashhad, Islamic Republic of ran 2 Young Researchers Club and elites, Mashhad Branch, Islamic Azad University, Mashhad, Islamic Republic of ran 3 Department of Geology, Faculty of Sciences, Ferdowsi University of Mashhad, Islamic Republic of ran Received: 10 June 2013 / Revised: 15 July 2013 / Accepted: 19 August 2013 Abstract Abderaz Formation is one of the Upper Cretaceous formations in the Kopet- Dagh sedimentary basin. A stratigraphic section from the mentioned formation is selected for detailed systematic description with regard to echinoids. Numerous well preserved representatives of the families Mircrasteridae wright, 1857 and Echinocorythidae Lambert, 1920 are described from the Ghaleh-Zoo stratigraphic section in the Kopet-Dagh sedimentary basin, northwest of Shirvan township (NE Iran). The age of the fossil assemblage is determined as Turonian-Santonian based on four echinoid species: Micraster (Micraster) coranguinum Leske, 1778, Micraster (Micraster) cortestudinarium (Goldfuss, 1829), Echinocorys gravesi (Agassiz & Desor, 1847) and Echinocorys ex gr. scutata Leske, 1778. Keywords: Echinoids; Late Cretaceous; Kopet-Dagh; NE Iran proposed by geologists of the National Iranian Oil Introduction Company [2 & 3]. According to the palaeontological Irregular echinoids first appeared in the Early investigations by Kalantari (1969) in the Sheikh and Jurassic and diversified markedly during the Cretaceous Zangulalu stratigraphic sections, the age is determined and Cenozoic, attaining a near-worldwide distribution. as Turonian-Santonian. The Abderaz Formation is In the Turonian and Coniacian, the group was represented by monotonous bluish-grey to light green- dominated by members of the orders Spatangoida and grey shales. It conformably overlies the Atamir Holasteroida. The former is represented mainly by the Formation and is overlain by the Abtalkh Formation genus Micraster, the latter by Echinocorys [21]. This (figs. 2-3). In the eastern part of the Kopet-Dagh the study aims to present the results on the echinoids for the formation attains a thickness of 500 m in the southeast Abderaz Formation in the West of Kopet-Dagh (Shurijeh) and 1500 m in the northwest (Taher Abad). sedimentary basin. The formation is rich in foraminifera which indicate The Abderaz Formation (named after the village of Turonian-Santonian age. The Turonian age is Abderaz in southeastern Kopet-Dagh basin) was represented by 58 m of chalky limestones and * Corresponding author, Tel: 0098-915-1025900, Fax: 0098-511- 8403490, E-mail: [email protected] 243 Vol. 24 No. 3 Summer 2013 J. Noorbakhsh Razmi et al. J. Sci. I. R. Iran Figure 1. Location of the studied section in NE Iran calcareous shales containing Ataxophtagmium puschi, Frondicularia cordata, Globotruncana helvetica, Globotruncana imbricata, Globotruncana linneiformis and Marsonella turris. As well, the Coniacian stage, 25 m thick is composed of marly limestones and calcareous shales, indicated by Gavellinella costata, Globotruncana culverensis and Globotruncana schneegansi. The grey marly limestones and black calcareous shales, about 750 m thick, are attributed to the Santonian on the basis of the following assemblage: Globotruncana concavata carinata, Globotruncana lapparenti coronate, Globotruncana lapperenti lapperenti, Globotruncana fornicata, Neoflabellina ovalis and Stensioina exculpta [29]. Figure 2. The gradual boundary between Atamir and Geological setting Abderaz formations The NE active fold belt of Iran, Kopet-Dagh, is formed on Hercynian metamorphosed basement at the SW margin of the Turan Platform. The Kopet-Dagh region of NE Iran exposes rather complete Jurassic sections, which reach thickness of about 3000 m. The belt is composed of about 10 km thick Mesozoic and Tertiary sediments (mostly carbonates) and like the Zagros, was folded into long linear NW-SE trending folds during the last phase of the Alpine Orogeny, in the Plio-Pleistocene time. No igneous rocks are exposed in Kopet-Dagh except for those in the basement in Aghdarband tectonic window [29]. The Shirvan area is a part of the Kopet-Dagh sedimentary basin which is located in northern Khorasan province. The Ghaleh-Zoo stratigraphic Figure 3. The gradual boundary between Abderaz section is located 21 km northwest from Shirvan and Kalat formations 244 Morphological and systematic interpretation of some Late Cretaceous (Turonian-Santonian) irregular… township (37 31’ 23’’N and 57 47’ 24’’E). The Abderaz to be taken into the every part of the body. Echinoderms and Kalat formations are well-exposed in the studied developed an internal calcareous skeleton, the so-called area. In this study the Abderaz Formation is investigated theca, which consist of fixed plates or plates of CaCO3 in the Ghaleh-Zoo stratigraphic section with regard to connected by joints. The name of this entire phylum is echinoids (Fig.1). based on the fact that there are usually numerous spines sticking through the skin and covers the calcareous skeleton to appear on the surface. Living representatives Previous studies in the Middle East of the echinoderms are subdivided into five classes and In the Kopeh-Dagh region, the first study on the of these the subphyla Blastozoa, Crinozoa and echinoderms of the Abderaz Formation (Turonian- Echinozoa are particularly important for paleontology Coniacian) was carried out by Vahidinia & Aryaei, [15]. 2000 and those of the Tirgan Formation by Hashemian The material studied comprises almost 150 et al., 2007. Likewise, a study on the Early Cretaceous specimens and have been analyzed biometrically. Most echinoderms of central Iran was carried out by of the specimens studied were collected by the author Yaghoubi et al., (2008). The latest work on the Early and are now housed at the Department of Geology, Cretaceous echinoderms in the Kopet-Dagh basin Mashhad Branch, Islamic Azad University, Mashhad, (Tirgan Formation) is carried out by Taherpour Khalil Iran and used the IAUM (Islamic Azad University, Abad et al. (2011). In this report, some specious are Mashhad Branch) as the prefix abbreviation. attributed to Toxaster (i.e. T. renevieri, T. collegnii, T. granosus), Heteraster (i.e. H. cf. delgadoi) and Loriolia. Meanwhile, from elsewhere some species such as Heteraster musandamensis (Aptian age) and Heteraster Systematic Descriptions aff. couloni (index for Hauterivian-Barremian age) are The systematic is given following the latest concepts reported from upper Musandam limestone [14], by Smith (1984), Smith & Wright (1999, 2000, 2003) Heteraster oblongus of the Early Aptian [5], in the and descriptive terminology by Durham & Wagner United Arab Emirates. Toxaster radula, Toxaster lamberti, Toxaster dieneri and Toxaster collegnoi have been reported from the Aptian of Risan Aneiza Formation [1] in Egypt, Heteraster oblongus is reported from the Barremian of Qishn Formation [13] in Yemen; Heteraster oblongus from Sarmord Formation in North Iraq, Toxaster retusus from Turkmenistan [4], Heteratser delgadoi from the Palmyrides chain in Central Syria [1] and Heteraster renngarteni from Central Syria [35]. Figure 4. Basic measurements in the genus Micraster Agassiz, 1836; L – length of the test (in mm); W – width of the test (in mm); H – height of the test (in mm); WT – Materials and Methods width of the test measured at one third from posterior edge (in mm); AA – anal angle (in degrees); a – distance Echinoderms are marine, solitary and usually benthic from central point of apical disc to anterior edge (in mm); animals. They were diverse in shapes (in ambulacra, b – distance from central point of apical disc to posterior genital plates and etc.) in this phylum from the Early edge (in mm) (Olszewska-Nejbert, 2007). Paleozoic. Echinoderms are characterized by the presence of an ambulacral system. This organ helps the animal in food obtaining, the vascular system, the respiratory system, as well as organs for locomotion. The system starts at the surface with an opening known as the hydropore, or with a perforated calcareous madrepore plate. Water which circulates through the ambulacral system not only provides the organism with oxygen, but Figure 5. Basic measurements in the genus Echinocorys also moves microscopic particles of food towards the Leske, 1778; L – length of test; W – width of test; H – height of test; HE – height of ambitus (Olszewska- mouth. Water penetrates this to the water vascular Nejbert, 2007). system, gradually passing into the radial canal in order 245 Vol. 24 No. 3 Summer 2013 J. Noorbakhsh Razmi et al. J. Sci. I. R. Iran (1966) and Olszewska (2007). Also, in the systematic Biometric calculations: The characters which are paleontology studies, the biometric parameters are measured and abbreviations used for representatives of calculated in order to describe the genus and specious in this family are shown in tables 1-6. the best way. The results of these calculations are described in the biometric calculation part. Occurence: The genus Micraster first occurs in the Order SPATANGOIDA Agassiz, 1840 Cenomanian (Devon, England, e.g. Smith 1988) and Infraorder MICRASTERINA Fischer, 1966